The present invention relates generally to systems for steering and suspension of the steerable wheels of vehicles and more particularly to such systems adapted for three-wheeled vehicles for inducing leaning of the vehicle frame during turning of the vehicle.
In recent years, the increasing costs of gasoline have produced a substantial amount of activity toward the development of more efficient, compact and lighter weight vehicles. While such development work has predominantly been devoted to the modification and improvement of conventional automotive vehicles, some activity has been devoted to the development of generally unconventional vehicles. For instance, three-wheeled vehicles offer advantages and design possibilities substantially unavailable with conventional automotive vehicles in terms of greater possible reduction of the weight of the overall vehicle, reduced power requirements, a normally lesser rolling resistance resulting from the fewer number of wheels utilized, a wider and more varied range of aerodynamic exterior body configurations, etc., all of which permit the achievement of substantially increased operational efficiencies over more conventional vehicles. Furthermore, three-wheeled vehicles make available rather unconventional engineering possibilities in the design of the vehicle steering and suspension arrangements to improve the stability of vehicle handling and turning capabilities.
Conventional personal automotive vehicles are known to suffer significant deficiencies in steering and general handling capability due to the steering and suspension systems typically employed therein. As is well known, during the turning of a conventional automotive vehicle, centrifugal force acts upon the vehicle radially outwardly of the turn creating a tendency of the vehicle to roll about an axis extending longitudinally of the vehicle. Conventionally, this problem is brought within acceptable limits by the construction of steering and suspension systems having a roll axis relatively low to the ground and the rigidifying of the suspension system with "anti-sway" or similar arrangements. However, the tendency of the vehicle to roll during turning still exists in these vehicles, the primary effect of such steering and suspension arrangements being to require greater centrifugal forces to initiate roll.
In the past, various types of vehicle steering and suspension systems have been proposed to improve vehicle handling by counteracting centrifugal forces during turning by mechanically providing for the leaning of the vehicle radially inwardly of turns correspondingly to shift the center of gravity of the vehicle inwardly. See, for example, U.S. Pat. Nos. 1,283,942; 2,029,735; 2,053,294; 2,260,102; 2,493,817; 3,447,623; 3,746,118; 3,964,563; 4,020,914; 4,072,325; 4,088,199; and 4,360,224. Mechanically-induced vehicle leaning is perhaps best adapted to three-wheeled vehicles, the above-referenced U.S. Pat. No. 3,964,563 disclosing one particular proposed arrangement for this purpose which employs a mechanism intercoupling two transversely-spaced wheels for automatic opposed reciprocatory pivotal movement upwardly and downwardly for inducing vehicle leaning inwardly of any turning movement of the vehicle.
The present invention provides a novel steering and suspension system characterized by its compact, lightweight and simple construction so as to be particularly adapted for use in three-wheeled vehicles and which, in one embodiment thereof, provides for the inducement of leaning of the vehicle during turning to improve the handling stability of the vehicle.